What is Google Search Quality Rater Guidelines?
Google Search Quality Rater Guidelines is a set of instructions that Google’s human evaluators (called Search Quality Raters or Raters) use to assess the quality of Google results pages. The instructions are currently documented in a PDF file available here.
Raters are third-party employees who assess the quality of webpages in Google search results. They perform multiple tasks, including entering search queries into Google and then using the quality rater guidelines to rate the quality of the search results page.
Raters also use the quality rater guidelines to decide whether Google’s current or proposed algorithm update meets Google’s goal of presenting relevant and reliable results to searchers. Google says that raters do not directly affect the rankings of search results.